Glutamate release evoked by glutamate receptor agonists in cultured chick retina cells: modulation by arachidonic acid.
AuthorsDuarte CB,Santos PF,Sánchez-Prieto J,Carvalho AP
JournalJournal of neuroscience research
PubMed ID8739156
Cultured chick-embryo heart cells respond differently to ouabain as measured by the increase in their intracellular Na+ concentration.
AuthorsAhlemeyer B, Weintraut H, Schoner W
JournalBiochim Biophys Acta
PubMed ID1420320
Using digital imaging microscopy with the sodium-sensitive fluorescent indicator sodium-binding benzofuran isophtalate (SBFI), we examined the cytosolic free sodium ion concentration ([Na+]i) in single chick-embryo heart cells. The distribution of the [Na+]i was homogeneous within one cell, but we found a wide cell to cell variation in the range of ... More
Effect of vasopressin on Na+ kinetics in cultured rat vascular smooth muscle cells.
AuthorsOkada K, Ishikawa S, Saito T
JournalBiochem Biophys Res Commun
PubMed ID2124111
The effect of arginine vasopressin (AVP) on Na+ kinetics was examined in cultured rat vascular smooth muscle cells (VSMC) and rat renal papillary collecting tubule cells (RPCT) by the direct measurement of intracellular sodium concentration [(Na+]i) using fluorescence dye; SBFI. AVP increased [Na+]i in a dose-dependent manner at a concentration ... More
Mechanism of collagen activation in human platelets.
AuthorsRoberts DE, McNicol A, Bose R
JournalJ Biol Chem
PubMed ID14981087
The mechanism of collagen-induced human platelet activation was examined using Ca2+, Na+, and the pH-sensitive fluorescent dyes calcium green/fura red, sodium-binding benzofuran isophthalate, and 2',7'-bis(2-carboxyethyl)-5(6)-carboxyfluorescein. Administration of a moderate dose of collagen (10 microg/ml) to human platelets resulted in an increase in [Ca2+](i) and platelet aggregation. The majority of this ... More
Expression of the voltage-gated sodium channel NaV1.5 in the macrophage late endosome regulates endosomal acidification.
AuthorsCarrithers MD, Dib-Hajj S, Carrithers LM, Tokmoulina G, Pypaert M, Jonas EA, Waxman SG,
JournalJ Immunol
PubMed ID17548620
'Voltage-gated sodium channels expressed on the plasma membrane activate rapidly in response to changes in membrane potential in cells with excitable membranes such as muscle and neurons. Macrophages also require rapid signaling mechanisms as the first line of defense against invasion by microorganisms. In this study, our goal was to ... More
Plasma membrane expression of T-type calcium channel alpha(1) subunits is modulated by high voltage-activated auxiliary subunits.
'It has been suggested that the auxiliary subunits of high voltage-activated (HVA) calcium channels modulate T-type, low voltage-activated (LVA) calcium channels. Such a regulation has yet to be documented, especially because there has been no biochemical characterization of T-channels. To monitor total protein levels and plasma membrane expression of T-channels ... More
Na+-dependent release of Mg2+ from an intracellular pool in rat sublingual mucous acini.
AuthorsZhang GH, Melvin JE
JournalJ Biol Chem
PubMed ID8910560
'Muscarinic stimulation induces release of Mg2+ from an intracellular pool in rat sublingual mucous acini (Zhang, G. H., and Melvin, J. E. (1992) J. Biol. Chem. 267, 20721-20727). In the present study we examined the interdependence of Mg2+ mobilization on intracellular Na+ and Ca2+ by monitoring the intracellular free concentrations ... More
Phytoestrogen cimicifugoside-mediated inhibition of catecholamine secretion by blocking nicotinic acetylcholine receptor in bovine adrenal chromaffin cells.
AuthorsWoo KC, Park YS, Jun DJ, Lim JO, Baek WY, Suh BS, Kim KT
JournalJ Pharmacol Exp Ther
PubMed ID14757852
'We investigated the effect of the phytoestrogen cimicifugoside, one of the pharmacologically active ingredients of the medicinal plant Cimicifuga racemosa (black cohosh) that has been used to treat many kinds of neuronal and menopausal symptoms, such as arthritis, menopausal depression, and nerve pain. Cimicifugoside inhibited calcium increase induced by 1,1-dimethyl-4-phenylpiperazinium ... More
The spread of Na+ spikes determines the pattern of dendritic Ca2+ entry into hippocampal neurons.
AuthorsJaffe DB, Johnston D, Lasser-Ross N, Lisman JE, Miyakawa H, Ross WN
JournalNature
PubMed ID1350327
'The dendrites of many types of neurons contain voltage-dependent Na+ and Ca2+ conductances that generate action potentials (see ref. 1 for review). The function of these spikes is not well understood, but the Ca2+ entry stimulated by spikes probably affects Ca(2+)-dependent processes in dendrites. These include synaptic plasticity, cytotoxicity and ... More
Ouabain interaction with cardiac Na+/K+-ATPase initiates signal cascades independent of changes in intracellular Na+ and Ca2+ concentrations.
AuthorsLiu J, Tian J, Haas M, Shapiro JI, Askari A, Xie Z
JournalJ Biol Chem
PubMed ID10874029
'We have shown previously that partial inhibition of the cardiac myocyte Na(+)/K(+)-ATPase activates signal pathways that regulate myocyte growth and growth-related genes and that increases in intracellular Ca(2+) concentration ([Ca(2+)](i)) and reactive oxygen species (ROS) are two essential second messengers within these pathways. The aim of this work was to ... More
Hyperforin, a major antidepressant constituent of St. John's Wort, inhibits serotonin uptake by elevating free intracellular Na+1.
AuthorsSinger A, Wonnemann M, Müller WE
JournalJ Pharmacol Exp Ther
PubMed ID10454515
'Extracts of Hypericum perforatum (St. John's Wort) are widely used for the treatment of depressive disorders and are unspecific inhibitors of the neuronal uptake of several neurotransmitters. Previous studies have shown that hyperforin represents the reuptake inhibiting constituent. To characterize the mechanism of serotonin reuptake inhibition, kinetic analyses in synaptosomes ... More
Intracellular free Na+ in resting and activated A7r5 vascular smooth muscle cells.
AuthorsBorin ML, Goldman WF, Blaustein MP
JournalAm J Physiol
PubMed ID8333503
'Regulation of intracellular Na+ ([Na+]i) in cultured vascular smooth muscle cells (A7r5 line) was studied with Na(+)-sensitive fluorescent dye sodium-binding benzofuran isophthalate. Digital imaging microscopy was used to study single-cell fluorescence. Na+ was distributed uniformly in cytoplasm and nucleus; mean Na+ concentration in resting cells was 4.4 +/- 0.3 mM ... More
Further characterization of the mechanisms mediating the rise in cytosolic free Na+ in thrombin-stimulated platelets. Evidence for inhibition of the Na+,K(+)-ATPase and for Na+ entry via a Ca2+ influx pathway.
AuthorsBorin M, Siffert W
JournalJ Biol Chem
PubMed ID1649180
'Human platelets were loaded with the fluorescent Na(+)-sensitive dye sodium-binding benzofuran isophtalate (SBFI), and changes in the fluorescence excited at 345 and 385 nm were analyzed after manipulations that evoked predictable changes in the cytosolic Na+ concentration ([Na+]i). Raising [Na+]i by either gramicidin D or monensin specifically increased the fluorescence ... More
Suppression of Ca2+ oscillations in cultured rat hepatocytes by chemical hypoxia.
AuthorsKawanishi T, Nieminen AL, Herman B, Lemasters JJ
JournalJ Biol Chem
PubMed ID1939069
'The model of "chemical hypoxia" with KCN plus iodoacetic acid mimics the ATP depletion and reductive stress of hypoxia. Here, we examined the effects of chemical hypoxia on cytosolic free Na+ and Ca2+ in single cultured rat hepatocytes by multiparameter digitized video microscopy and ratio imaging of sodium-binding furan indicator ... More
Activity of ionotropic glutamate receptors in retinal cells: effect of ascorbate/Fe(2+)-induced oxidative stress.
AuthorsAgostinho P, Duarte CB, Oliveira CR
JournalJ Neurochem
PubMed ID8752122
'The effect of oxidative stress induced by the oxidant pair ascorbate/Fe2+ on the activity of ionotropic glutamate receptors was studied in cultured chick retina cells. The release of [3H]GABA and the increase of the intracellular free Na+ concentration ([Na+]i), evoked by glutamate receptor agonists, were used as functional assays for ... More
Regulation of changes in cytosolic Ca2+ and Na+ concentrations in rat submandibular gland acini exposed to carbachol and ATP.
AuthorsHurley TW, Ryan MP, Moore WC
JournalJ Cell Physiol
PubMed ID8707858
'The relationship between cytosolic concentrations of Ca2+ (Ca2i) and Na+ (Na+i) were studied in preparations of rat submandibular and pancreatic acini loaded with the Ca(2+)-sensitive dye Fura-2 or the Na(+)-sensitive dye SBFI. Pancreatic acini showed no changes in Na+i during either transient or persistent changes in Ca2+i. Increases in Ca2+i ... More
Accumulation of intracellular HCO3- by Na(+)-HCO3- cotransport in interlobular ducts from guinea-pig pancreas.
AuthorsIshiguro H, Steward MC, Lindsay AR, Case RM
JournalJ Physiol
PubMed ID8866360
'1. Short segments of interlobular duct were microdissected from guinea-pig pancreas following enzymatic digestion. After overnight culture, intracellular pH (pH1) and Na+ concentration ([Na+]i) were measured by microfluorometry in duct cells loaded with either the pH-sensitive fluoroprobe 2''7''-bis(2-carboxyethyl)-5(6)-carboxyfluorescein (BCECF) or the sodium-binding benzofuran isophthalate (SBFI). 2. The transporters responsible for ... More
Intracellular sodium changes during the speract response and the acrosome reaction in sea urchin sperm.
AuthorsRodríguez E, Darszon A
JournalJ Physiol
PubMed ID12509481
'The sperm-activating peptide speract and fucose-sulphate glycoconjugate (FSG) are sea urchin egg-envelope components that modulate sperm ion permeability. They influence motility and induce acrosomal reaction (AR), respectively. A fluorescent Na(+)-sensitive dye (Na(+)-binding benzofuran isophthalate, SBFI) was used to determine how these egg envelope components influence sperm Na(+) permeability. [Ca(2+)](i) and ... More
'Mechanically poking or damaging a single cell within a confluent astrocyte culture produces the so-called intercellular calcium (Ca(2+)) waves, that is, cell-to-cell propagating changes of intracellular free Ca(2+). We were interested whether intercellular Ca(2+) waves are also associated with changes in other intra- or extracellular ions. To that purpose, we ... More
Brain-derived neurotrophic factor stimulates energy metabolism in developing cortical neurons.
AuthorsBurkhalter J, Fiumelli H, Allaman I, Chatton JY, Martin JL
JournalJ Neurosci
PubMed ID12967982
'Brain-derived neurotrophic factor (BDNF) promotes the biochemical and morphological differentiation of selective populations of neurons during development. In this study we examined the energy requirements associated with the effects of BDNF on neuronal differentiation. Because glucose is the preferred energy substrate in the brain, the effect of BDNF on glucose ... More
The role of Na+/H+ exchange and the Na+/K+ pump in the regulation of [Na+]i during metabolic inhibition in guinea pig myocytes.
AuthorsKatoh H, Satoh H, Nakamura T, Terada H, Hayashi H
JournalBiochem Biophys Res Commun
PubMed ID8074732
'To investigate the mechanisms of Na+ loading during metabolic inhibition (MI), [Na+]i and pHi were measured in quiescent guinea pig myocytes using fluorescent probes, sodium-binding benzofuran isophthalate and 2,7,bis(carboxyethyl)-5,6-carboxyfluorescein. When myocytes were exposed to MI (3.3 mM amobarbital and 5 microM carbonyl cyanide m-chlorophenylhydrazone, without glucose) for 20 min, [Na+]i ... More
Mode of antinociceptive and toxic action of alkaloids of Aconitum spec..
'Extracts of the plant Aconitum spec. are used in traditional Chinese medicine predominantly as anti-inflammatory and analgesic agents, the latter allegedly equally potent as morphine but without any habit-forming potential. As the only pharmacologically active compounds, the C19 diterpenoid alkaloid aconitine, and some of its derivatives, have been proven to ... More
Activation of muscarinic receptors increases the concentration of free Na+ in mouse pancreatic B-cells.
AuthorsGilon P, Henquin JC
JournalFEBS Lett
PubMed ID8380774
'The fluorescent probe SBFI was used to monitor the influence of acetylcholine (ACh) on the cytosolic concentration of free Na+ (Na+i) in single mouse pancreatic B-cells. In the presence of 3 mM glucose and 135 mM extracellular Na+, Na+i averaged 16.6 mM. ACh (100 microM) increased Na+i by approximately 80%. ... More
Activation of the Na(+)-H+ exchanger modulates angiotensin II-stimulated Na(+)-dependent Mg2+ transport in vascular smooth muscle cells in genetic hypertension.
AuthorsTouyz RM, Schiffrin EL
JournalHypertension
PubMed ID10489391
'This study investigated the role of the Na(+)-H+ exchanger (NHE) on angiotensin II (Ang II)-induced activation of Na(+)-dependent Mg2+ transport in vascular smooth muscle cells (VSMCs) from Wistar-Kyoto rats (WKY; n=20) and spontaneously hypertensive rats (SHR; n=20). Intracellular free concentrations of Mg2+ ([Mg2+]i) and Na+ ([Na+]i) and intracellular pH (pHi) ... More
Characterization of the participation of sodium channels on the rise in Na+ induced by 4-aminopyridine (4-AP) in synaptosomes.
AuthorsGalván E, Sitges M
JournalNeurochem Res
PubMed ID15002730
'The participation of voltage-sensitive Na+ channels (VSSC) on the changes on internal (i) Na+, K+, Ca2+, and on DA, Glu, and GABA release caused by different concentrations of 4-AP was investigated in striatum synaptosomes. TTX, which abolished the increase in Na(i) (as determined with SBFI), induced by 0.1 mM 4-AP ... More
The alkaloid 6-benzoylheteratisine inhibits voltage-gated Na+ channels in rat brain synaptosomes.
AuthorsGutser UT, Gleitz J
JournalNeuropharmacology
PubMed ID9833644
'The effects of the Aconitum alkaloid 6-benzoylheteratisine on the aconitine-, veratridine-, oubain- and KCl-induced alterations in free synaptosomal Na + ([Na+]i) and Ca2+ ([Ca2+]i) and the release of endogenous glutamate from rat cerebrocortical synaptosomes were investigated. [Na+]i and [Ca2+]i were fluorometrically determined employing SBFI and Fura-2 as the Na+ and ... More
Mechanisms of Mg(2+) transport in cultured ruminal epithelial cells.
AuthorsSchweigel M, Vormann J, Martens H
JournalAm J Physiol Gastrointest Liver Physiol
PubMed ID10712259
'Net Mg(2+) absorption from the rumen is mainly mediated by a transcellular pathway, with the greater part (62%) being electrically silent. To investigate this component of Mg(2+) transport, experiments were performed with isolated ruminal epithelial cells (REC). Using the fluorescent indicators mag-fura 2, sodium-binding benzofuran isophthalate, and 2'', 7''-bis(2-carboxyethyl)-5(6)-carboxyfluorescein, we ... More
Determination of the physical environment within the Chlamydia trachomatis inclusion using ion-selective ratiometric probes.
AuthorsGrieshaber S, Swanson JA, Hackstadt T
JournalCell Microbiol
PubMed ID12027956
'Chlamydia trachomatis is an obligate intracellular bacterium with a biphasic life cycle that takes place entirely within a membrane-bound vacuole termed an inclusion. The chlamydial inclusion is non-fusogenic with endosomal or lysosomal compartments but intersects a pathway involved in transport of sphingomyelin from the Golgi apparatus to the plasma membrane. ... More
Role of [Na+]i and [Ca2+]i in nicotine-induced norepinephrine release from bovine adrenal chromaffin cells.
AuthorsGerber SH, Haunstetter A, Krüger C, Kaufmann A, Nobiling R, Haass M
JournalAm J Physiol
PubMed ID7573386
'Intracellular free sodium ([Na+]i) and calcium ([Ca2+]i) concentrations were determined by sodium-binding benzofuran isophthalate (SBFI) and fura 2 microfluorimetry, respectively, in bovine adrenal chromaffin cells (BCC). Validation of SBFI microfluorimetry by in vitro and in vivo calibration revealed a reliable assessment of [Na+]i within a range of 1-30 mM in ... More
Na+/H+ and Na+/Ca2+ exchange in regulation of [Na+]i and [Ca2+]i during metabolic inhibition.
AuthorsSatoh H, Hayashi H, Katoh H, Terada H, Kobayashi A
JournalAm J Physiol
PubMed ID7900878
'The relationships among intracellular Na+ and Ca2+ concentrations ([Na+]i and [Ca2+]i, respectively) and cell morphology were investigated during metabolic inhibition (MI) in isolated guinea pig myocytes. [Na+]i and [Ca2+]i were measured using the fluorescent indicators, Na(+)-binding benzofuran isophthalate and fluo 3. During the initial 20 min of MI, [Na+]i increased ... More
Induction of cytosolic Ca2+ elevation mediated by Mas-7 occurs through membrane pore formation.
AuthorsSuh BC, Song SK, Kim YK, Kim KT
JournalJ Biol Chem
PubMed ID8955110
'Mas-7, a mastoparan derivative, induces elevation of intracellular free Ca2+ concentration ([Ca2+]i) along two independent pathways. The minor contribution occurs via phospholipase C activation and is negatively regulated by treatment with phorbol 12-myristate 13-acetate, a protein kinase C activator. The major contribution involves plasma membrane pores allowing not only Ca2+, ... More
Identification of lymphocyte 5-HT3 receptor subtype and its implication in fish T-cell proliferation.
AuthorsMeyniel JP, Khan NA, Ferrière F, Deschaux P
JournalImmunol Lett
PubMed ID9161881
'In the present study, we identified the serotonergic receptor of type 3 (5-HT3) on the lymphocytes of a teleost fish, Oncorhynchus mykiss. In the pharmacological studies on the binding of [3H]serotonin to membrane receptor sites, 2-methyl-5-HT, an agonist of 5-HT3 receptors, displaced the binding of [3H]serotonin to fish lymphocytes, indicating ... More
Differential stimulation of the Na+/H+ exchanger determines chloroquine uptake in Plasmodium falciparum.
AuthorsWünsch S, Sanchez CP, Gekle M, Grosse-Wortmann L, Wiesner J, Lanzer M
JournalJ Cell Biol
PubMed ID9442109
'Here we describe the identification and characterization of a physiological marker that is associated with the chloroquine-resistant (CQR) phenotype in the human malarial parasite Plasmodium falciparum. Single cell in vivo pH measurements revealed that CQR parasites consistently have an elevated cytoplasmic pH compared to that of chloroquine-sensitive (CQS) parasites because ... More
Characterization of Na+ transport across the cell membranes of the ascending thin limb of Henle's loop.
AuthorsTakahashi N, Kondo Y, Fujiwara I, Ito O, Igarashi Y, Abe K
JournalKidney Int
PubMed ID7752578
'In the ascending thin limb of Henle''s loop (ATL), intracellular Na+ is extruded by Na+/K+ ATPase in the basolateral membrane. To further characterize Na+ transport across the cell membranes of the ATL, the intracellular sodium concentration ([Na+]i) was monitored using a sodium-sensitive fluorescent probe, SBFI, in the in vitro microperfused ... More
Elevation of intradendritic sodium concentration mediated by synaptic activation of metabotropic glutamate receptors in cerebellar Purkinje cells.
AuthorsKnöpfel T, Anchisi D, Alojado ME, Tempia F, Strata P
JournalEur J Neurosci
PubMed ID10886360
'Cerebellar Purkinje cells express both ionotropic glutamate receptors and metabotropic glutamate receptors. Brief tetanic stimulation of parallel fibers in rat and mouse cerebellar slices evokes a slow excitatory postsynaptic current in Purkinje cells that is mediated by the mGluR1 subtype of metabotropic glutamate receptors. The effector system underlying this mGluR1 ... More
Gap junction-mediated intercellular biochemical coupling in cochlear supporting cells is required for normal cochlear functions.
AuthorsZhang Y, Tang W, Ahmad S, Sipp JA, Chen P, Lin X
JournalProc Natl Acad Sci U S A
PubMed ID16217030
'Dysfunction of gap junctions (GJs) caused by mutations in connexin26 (Cx26) and Cx30 accounts for nearly half of all cases of hereditary nonsyndromic deafness cases. Although it is widely held that GJs connecting supporting cells in the organ of Corti mainly provide ionic pathways for rapid removal of K+ around ... More
Thyroid hormone stimulates Na(+)-Ca2+ exchanger expression in rat cardiac myocytes.
AuthorsHojo Y, Ikeda U, Tsuruya Y, Ebata H, Murata M, Okada K, Saito T, Shimada K
JournalJ Cardiovasc Pharmacol
PubMed ID9007674
'We investigated whether thyroid hormone directly affects Na(+)-Ca2+ exchanger expression in cardiac myocytes. Cultured neonatal rat cardiocytes were prepared from 1-day-old Sprague-Dawley rats. Intracellular Na+ concentration ([Na+]i) in cardiocytes was measured by using the Na(+)-sensitive dye sodium-binding benzofran isophthalate (SBFI). Na(+)-Ca2+ exchanger messenger RNA (mRNA) and protein expression were assayed ... More
Effects of the Anemonia sulcata toxin (ATX II) on intracellular sodium and contractility in rat and guinea-pig myocardium.
AuthorsHoey A, Harrison SM, Boyett MR, Ravens U
JournalPharmacol Toxicol
PubMed ID7899257
'The effects of the Anemonia sulcata toxin ATX II on action potentials and contractility of isolated papillary muscles and single myocytes from rat and guinea-pig hearts have been studied. ATX II prolonged the action potential in both rat and guinea-pig papillary muscle. Although it produced a positive inotropic effect in ... More
Uncoupling cell shrinkage from apoptosis reveals that Na+ influx is required for volume loss during programmed cell death.
AuthorsBortner CD, Cidlowski JA
JournalJ Biol Chem
PubMed ID12821680
'Cell shrinkage, or the loss of cell volume, is a ubiquitous characteristic of programmed cell death that is observed in all examples of apoptosis, independent of the death stimulus. This decrease in cell volume occurs in synchrony with other classical features of apoptosis. The molecular basis for cell shrinkage during ... More
A primary role for K+ and Na+ efflux in the activation of apoptosis.
AuthorsBortner CD, Hughes FM, Cidlowski JA
JournalJ Biol Chem
PubMed ID9405453
'Cell shrinkage is a major characteristic of apoptosis, but the mechanism and role of this process in cell death are poorly understood. The primary factor that controls volume regulation in all cells is ions, and thus we have examined the movement of ions at the single cell level in lymphocytes ... More
Functional innervation in tissue engineered models for in vitro study and testing purposes.
AuthorsSuuronen EJ, McLaughlin CR, Stys PK, Nakamura M, Munger R, Griffith M,
JournalToxicol Sci
PubMed ID15342958
'The biotechnology industry is rapidly expanding and the emerging field of tissue engineering is projected to have a high impact in the near future. Recently the field of cellular, drug, and prosthetic delivery has melded with the field of tissue engineering to make simulated tissues. In addition to their roles ... More
Astrocyte Na+ channels are required for maintenance of Na+/K(+)-ATPase activity.
AuthorsSontheimer H, Fernandez-Marques E, Ullrich N, Pappas CA, Waxman SG
JournalJ Neurosci
PubMed ID8182422
'Astrocytes in vitro and in situ have been shown to express voltage-activated ion channels previously thought to be restricted to excitable cells, including voltage-activated Na+, Ca2+, and K+ channels. However, unlike neurons, astrocytes do not generate action potentials, and the functional role of voltage-activated channels in astrocytes has been an ... More
Stimulation by thrombin increases the cytosolic free Na+ concentration in human platelets. Studies with the novel fluorescent cytosolic Na+ indicator sodium-binding benzofuran isophthalate.
AuthorsBorin M, Siffert W
JournalJ Biol Chem
PubMed ID2174043
'The new fluorescent Na+ indicator sodium-binding benzofuran isophthalate (SBFI) was used for determination of the cytosolic free Na+ concentration, [Na+]i, in human platelets. The dye could be loaded into platelets in the form of its acetoxymethyl ester (SBFI-AM). Calibration of the fluorescence in terms of [Na+]i was done by measuring ... More
Changes in myoplasmic sodium concentration during exposure to lactate in perfused rat heart.
AuthorsTurvey SE, Allen DG
JournalCardiovasc Res
PubMed ID7954611
'OBJECTIVE: The free myoplasmic sodium concentration ([Na+]i) is thought to change during acidosis and ischaemia in the mammalian heart. Although there are methods available for measuring [Na+]i in isolated cells or small preparations, none is very effective in the isolated heart, which is one of the best models for studying ... More
Detection of intracellular free Na+ concentration of synaptosomes by a fluorescent indicator, Na(+)-binding benzofuran isophthalate: the effect of veratridine, ouabain, and alpha-latrotoxin.
AuthorsDeri Z, Adam-Vizi V
JournalJ Neurochem
PubMed ID8360686
'A novel fluorescent Na+ indicator, Na(+)-binding benzofuran isophthalate (SBFI), was used to follow changes in the intracellular free Na+ concentration ([Na+]i) of synaptosomes. The dye, when loaded into synaptosomes in the form of its acetoxymethyl ester, was responsive to changes of [Na+]. Calibration was made using the 340/380 nm excitation ... More
The calcium response to the excitotoxin kainate is amplified by subsequent reduction of extracellular sodium.
AuthorsCourtney MJ, Enkvist MO, Akerman KE
JournalNeuroscience
PubMed ID8544981
'The relation between intracellular and extracellular [Na+] and [Ca2+] and membrane potential during stimulation of non-N-methyl-D-aspartate glutamate receptors has been studied in cerebellar granule cells using the fluorescent indicators SBFI, fura-2 and the bisoxonol membrane potential probe DiBaC4(3). Kainate increased both [Ca2+]i (intracellular [Ca2+]) and [Na+]i (intracellular [Na+]) and depolarized ... More
Fluorescence measurements of cytosolic free Na concentration, influx and efflux in gastric cells.
AuthorsNegulescu PA, Harootunian A, Tsien RY, Machen TE
JournalCell Regul
PubMed ID1712635
'Regulation of cytosolic free Na (Nai) was measured in isolated rabbit gastric glands with the use of a recently developed fluorescent indicator for sodium, SBFI. Intracellular loading of the indicator was achieved by incubation with an acetoxymethyl ester of the dye. Digital imaging of fluorescence was used to monitor Nai ... More
Clioquinol and pyrithione activate TRPA1 by increasing intracellular Zn2+.
AuthorsAndersson DA, Gentry C, Moss S, Bevan S,
JournalProc Natl Acad Sci U S A
PubMed ID19416844
'The antifungal and amoebicidal drug clioquinol (CQ) was withdrawn from the market when it was linked to an epidemic of subacute myelo-optico-neuropathy (SMON). Clioquinol exerts its anti-parasitic actions by acting as a Cu/Zn chelator and ionophore. Here we show that local injections of CQ produce mechanical hyperalgesia and cold hypersensitivity ... More
Presynaptic GABA(B) receptor modulation of glutamate exocytosis from rat cerebrocortical nerve terminals: receptor decoupling by protein kinase C.
AuthorsPerkinton MS, Sihra TS
JournalJ Neurochem
PubMed ID9523568
'GABA and the GABA(B) receptor agonist (-)-baclofen inhibited 4-aminopyridine (4AP)- and KCl-evoked, Ca2+-dependent glutamate release from rat cerebrocortical synaptosomes. The GABA(B) receptor antagonist CGP 35348, prevented this inhibition of glutamate release, but phaclofen had no effect. (-)-Baclofen-mediated inhibition of glutamate release was insensitive to 2 microg/ml pertussis toxin. As determined ... More
Evidence for Na(+)-Ca2+ exchange and Ca(2+)-induced Ca2+ release in a cultured vascular smooth muscle cell line from the rat.
AuthorsGillespie JI, Otun H, Greenwell JR, Dunlop W
JournalExp Physiol
PubMed ID1543582
'Measurements of intracellular calcium (Cai2+) and sodium (Nai+) have been made in single smooth muscle cells from the rat aortic cell line (A10) using the Ca(2+)- and Na(+)-sensitive dyes Fura-2 and SBFI (sodium-binding benzofuran isophthalate). The effects of manipulation of intracellular and extracellular Na+ on Cai2+ have been investigated. Reversal ... More
Intracellular Na+ measurements using sodium green tetraacetate with flow cytometry.
AuthorsAmorino GP, Fox MH
JournalCytometry
PubMed ID8582247
'Intracellular sodium concentration ([Na+]i) can be measured using SBFI with image analysis or spectrofluorometry. However, SBFI cannot be used with most flow cytometry systems, due to its requirement for dual excitation in the UV range. Recently a new sodium indicator, Sodium Green, was developed which can be used with flow ... More
Time course of myocardial sodium accumulation after burn trauma: a (31)P- and (23)Na-NMR study.
AuthorsSikes PJ, Zhao P, Maass DL, Horton JW
JournalJ Appl Physiol
PubMed ID11717236
'In this study, (23)Na- and (31)P- nuclear magnetic resonance (NMR) spectra were examined in perfused rat hearts harvested 1, 2, 4, and 24 h after 40% total body surface area burn trauma and lactated Ringer resuscitation, 4 ml. kg(-1). %(-1) burn. (23)Na-NMR spectroscopy monitored myocardial intracellular Na+ using the paramagnetic ... More
Inhibition of synaptosomal veratridine-induced sodium influx by antidepressants and neuroleptics used in chronic pain.
AuthorsDeffois A, Fage D, Carter C
JournalNeurosci Lett
PubMed ID8981487
'Veratridine-induced (10 microM) increases in intracellular sodium ([Na+]int) or calcium ([Ca2+]int) in rat cortical synaptosomes, measured with the fluorescent dyes SBFI or FLUO-3 were blocked by tetrodotoxin (IC50 Na+ 14 nM; Ca2+ 20 nM) and by a series of reference sodium channel blockers with neuroprotective (riluzole, lifarizine IC50 approximately 1-5 ... More
Changes in intracellular Na+ concentration evoked by nicotinic receptor activation in the guinea-pig adrenal chromaffin cells.
AuthorsIto S, Ohta T, Nakazato Y
JournalNeurosci Lett
PubMed ID9464632
'Using the whole-cell voltage clamp technique and microfluorometry with sodium-binding benzofuran isophthalate (SBFI), a nicotine-induced inward current and increase in the intracellular Na+ concentration ([Na+]in) were examined simultaneously in guinea-pig adrenal chromaffin cells. The increase in [Na+]in expected from the time-integrated inward current was well correlated with that of [Na+]in ... More
Thapsigargin increases cellular free calcium and intracellular sodium concentrations in cultured rat glomerular mesangial cells.
AuthorsIshikawa S, Fujisawa G, Okada K, Saito T
JournalBiochem Biophys Res Commun
PubMed ID8333842
'We examined whether thapsigargin increases cellular free calcium ([Ca2+]i) and intracellular sodium concentration ([Na+]i) in cultured rat glomerular mesangial cells. 1 x 10(-6) M Thapsigargin increased [Ca2+]i to 244.4 from 86.6 nM, an increase sustained at least during the 15 min observation period. Such an increase in [Ca2+]i was transient ... More
Early sodium elevations induced by combined oxygen and glucose deprivation in pyramidal cortical neurons.
AuthorsPisani A, Calabresi P, Tozzi A, Bernardi G, Knöpfel T
JournalEur J Neurosci
PubMed ID9824470
'We investigated the effects of oxygen (O2)/glucose deprivation on intracellular sodium concentration ([Na+]i) of cortical pyramidal cells in a slice preparation of rat frontal cortex. Intracellular recordings were combined with microfluorometric measurements of [Na+]i using the Na+-sensitive dye sodium-binding benzofuran isophthalate (SBFI). Deprivation of O2/glucose caused an initial membrane hyperpolarization ... More
Sustained depolarization and ADP-ribose activate a common ionic current in rat peritoneal macrophages.
AuthorsCampo B, Surprenant A, North RA
JournalJ Immunol
PubMed ID12538672
'Phagocytosis is associated with large changes in the membrane potential of macrophages, but the functional significance of this is unknown. Whole cell recordings were made from rat peritoneal macrophages. Sustained (>30 s) depolarization of the cells progressively activated a conductance that remained high (several nanoSeimens) for several tens of seconds. ... More
Isoproterenol stimulates rapid extrusion of sodium from isolated smooth muscle cells.
AuthorsMoore ED, Fay FS
JournalProc Natl Acad Sci U S A
PubMed ID8367463
'beta-Agonists cause an inhibition of contractility and a transient stimulation of Na+/K+ pumping in smooth muscle cells of the stomach from the toad Bufo marinus. To determine if the stimulation of Na+/K+ pumping causes changes in intracellular [Na+] ([Na+]i) that might link Na+ pump stimulation to decrease Ca2+ availability for ... More
The protective action of tetrodotoxin and (+/-)-kavain on anaerobic glycolysis, ATP content and intracellular Na+ and Ca2+ of anoxic brain vesicles.
AuthorsGleitz J, Tosch C, Beile A, Peters T
JournalNeuropharmacology
PubMed ID9076753
'Because recent reports point to Na+ channel blockers as protective agents directed against anoxia-induced neuronal damage including protection of anaerobic glycolysis, the influences of tetrodotoxin (TTX) and (+/-)-kavain on anoxic rat brain vesicles were investigated with respect to lactate synthesis, vesicular ATP content and cytosolic free Na+ and Ca2+ ([Na+]i, ... More
Effects of low extracellular Ca2+ on cytosolic free Ca2+, Na+, and pH of MDCK cells.
'The effects of lowering the Ca2+ electrochemical potential (delta mu Ca2+) by removing extracellular calcium (Ca2+o) was studied in Madin-Darby canine kidney (MDCK) cells. We measured cytosolic free calcium (Ca2+i), intracellular Na+ (Na+i), and intracellular pH (pHi) as well as Ca2+ and Na+ influx and efflux and H+ secretion. As ... More
Cell signaling pathways mediating epidermal growth factor stimulation of Na:K:2Cl cotransport activity in rabbit corneal epithelial cells.
AuthorsYang H, Wang Z, Miyamoto Y, Reinach PS
JournalJ Membr Biol
PubMed ID11562791
'We characterized the signaling and ion transport pathways that mediate epidermal growth factor receptor physiological control in SV40-immortalized rabbit corneal epithelial cells (tRCEC). Our evaluation employed single-cell fluorescence imaging to measure the intracellular [Na+]i in these cells loaded with the Na+ sensitive dye, SBFI. EGF (1 to 5 ng/ml) transiently ... More
Dehydroepiandrosterone sulfate inhibition of catecholamine secretion from bovine adrenal chromaffin cells.
AuthorsLiu PS, Lin MK, Hsieh HL
JournalNeurosci Lett
PubMed ID8938260
'Dehydroepiandrosterone sulfate (DHEAS) dose-dependently inhibited [3H]norepinephrine (NE) secretion and the corresponding [Ca2+]i rise induced by the nicotinic receptor agonist 1,1-dimethyl-4-phenylpoperazimium (DMPP) in bovine chromaffin cells. DHEAS at 10 microM, the physiological concentration in human serum, significantly inhibited both the release of [3H]NE and the rise of [Ca2+]i induced by DMPP ... More
Simultaneous measurement of intracellular Na+ and Ca2+ during K(+)-free perfusion in isolated myocytes.
AuthorsHayashi H, Satoh H, Noda N, Terada H, Hirano M, Yamashita Y, Kobayashi A, Yamazaki N
JournalAm J Physiol
PubMed ID8141255
'To study the relationship between intracellular Na+ concentration ([Na+]i) and intracellular Ca2+ concentration ([Ca2+]i), guinea pig ventricular myocytes were loaded with both the Na(+)-sensitive probe, sodium-binding benzofuran isophthalate (SBFI), and the Ca(2+)-sensitive probe, fluo 3. [Na+]i was measured from the ratio image at 510 nm when excited at 340/380 nm. ... More
Intracellular potassium stabilizes human ether-à-go-go-related gene channels for export from endoplasmic reticulum.
AuthorsWang L, Dennis AT, Trieu P, Charron F, Ethier N, Hebert TE, Wan X, Ficker E,
JournalMol Pharmacol
PubMed ID19139152
'Several therapeutic compounds have been identified that prolong the QT interval on the electrocardiogram and cause torsade de pointes arrhythmias not by direct block of the cardiac potassium channel human ether-à-go-go-related gene (hERG) but via disruption of hERG trafficking to the cell surface membrane. One example of a clinically important ... More
Dopamine-induced graded intracellular Ca2+ elevation via the Na+Ca2+ exchanger operating in the Ca2+-entry mode in cockroach salivary ducts.
AuthorsHille C, Walz B
JournalCell Calcium
PubMed ID16423391
'Stimulation with the neurotransmitter dopamine causes an amplitude-modulated increase in the intracellular Ca(2+) concentration ([Ca(2+)](i)) in epithelial cells of the ducts of cockroach salivary glands. This is completely attributable to a Ca(2+) influx from the extracellular space. Additionally, dopamine induces a massive [Na(+)](i) elevation via the Na(+)K(+)2Cl(-) cotransporter (NKCC). We ... More
Ca2+/Na+ exchanger and Na+,K+ 2Cl- cotransporter in lens fiber plasma membrane vesicles.
AuthorsYe JJ, Zadunaisky JA
JournalExp Eye Res
PubMed ID1486938
'When the Ca(2+)-sensitive fluorescent probe, Fura-2, or the Na(+)-sensitive probe, SBFI, in their cell permeable forms or the Cl(-)-specific probe, SPQ, were incubated with plasma membrane vesicles prepared from dogfish and bovine lenses fibers, there was a selective accumulation of the ion-specific probes within the vesicles. The SBFI and Fura-2 ... More
Dihydropiridines mechanism of action in striatal isolated nerve endings: comparison with omega-agatoxin IVA.
AuthorsGalindo CA, Sitges M
JournalNeurochem Res
PubMed ID15098927
'The relative contribution of Ca2+ and Na+ channels to the mechanism underlying the action of the dihydropiridines (DHPs), nimodipine, nitrendipine and nifedipine was investigated in rat striatum synaptosomes. The rise in internal Ca2+ (Ca(i), as determined with fura-2) induced by high K+ was unchanged by the DHPs, which like tetrodotoxin ... More
Increased cytosolic free sodium concentrations in platelets from type 2 (non-insulin-dependent) diabetic patients is associated with hypertension.
AuthorsTepel M, Bauer S, Husseini S, Raffelsiefer A, Zidek W
JournalJ Endocrinol
PubMed ID8277228
'Cytosolic free sodium concentrations ([Na+]i) in intact platelets from 32 type 2 (non-insulin-dependent) diabetic patients and from 27 age- and sex-matched non-diabetic control subjects were measured with the novel sodium-sensitive fluorescent dye sodium-binding-benzofuran-isophthalate. [Na+]i was significantly higher in platelets from type 2 diabetic patients compared with control subjects (40.6 +/- ... More
A sodium zinc exchange mechanism is mediating extrusion of zinc in mammalian cells.
AuthorsOhana E, Segal D, Palty R, Ton-That D, Moran A, Sensi SL, Weiss JH, Hershfinkel M, Sekler I
JournalJ Biol Chem
PubMed ID14581475
'Zinc influx, driven by a steep inward electrochemical gradient, plays a fundamental role in zinc signaling and in pathophysiologies linked to intracellular accumulation of toxic zinc. Yet, the cellular transport mechanisms that actively generate or maintain the transmembrane gradients are not well understood. We monitored Na+-dependent Zn2+ transport in HEK293 ... More
Effects of pH on Ca2+i, Na+i, and pHi of MDCK cells: Na(+)-Ca2+ and Na(+)-H+ antiporter interactions.
AuthorsBorle AB, Bender C
JournalAm J Physiol
PubMed ID1653523
'The effects of high and low extracellular pH (8.0 and 6.8) on the intracellular concentration of Ca2+, Na+, and H+ were measured in perfused Madin-Darby canine kidney (MDCK) cells cast in agarose gel threads. Cytosolic free Ca2+ (Ca2+i) was measured with aequorin, while intracellular Na+ (Na+i) and H+ (Hi+ or ... More
Intracellular free sodium concentrations in GH4C1 cells.
AuthorsTörnquist K, Ekokoski E
JournalJ Cell Physiol
PubMed ID8382212
'In the present investigation, intracellular sodium ([Na+]i) levels were determined in GH4C1 cells using the fluorescent probe SBFI. Fluorescence was determined by excitation at 340 nm and 385 nm, and emission was measured at 500 nm. Intracellular free sodium ([Na+]i) was determined by comparing the ratio 340/385 to a calibration ... More
Developmental profile and properties of sulforhodamine 101--Labeled glial cells in acute brain slices of rat hippocampus.
AuthorsKafitz KW, Meier SD, Stephan J, Rose CR,
JournalJ Neurosci Methods
PubMed ID18187203
'The reliable identification of astrocytes for physiological measurements was always time-consuming and difficult. Recently, the fluorescent dye sulforhodamine 101 (SR101) was reported to label cortical glial cells in vivo [Nimmerjahn A, Kirchhoff F, Kerr JN, Helmchen F. Sulforhodamine 101 as a specific marker of astroglia in the neocortex in vivo. ... More
Evidence from fluorescence microscopy and comparative studies that rat, ovine and bovine colonic crypts are absorptive.
AuthorsPedley KC, Naftalin RJ
JournalJ Physiol
PubMed ID8487207
'1. To test whether colonic crypts are secretory or absorptive interstitial [Na+] in rat descending colonic mucosa is determined using video-enhanced imaging of the impermeant acid form of the fluorescent Na+ probe SBFI (Molecular Probes) and intracellular [Na+] is monitored with SBFI (AM form). In rat descending colonic mucosa perifused ... More
Ionic effects of angiotensin II and their role in the activation of the Na+/H+ antiporter.
AuthorsFlores G, Ye M, LaPointe M, Batlle D
JournalKidney Int Suppl
PubMed ID8743531
'The possible interdependence of the effects of angiotensin II (Ang II) on intracellular pH (pHi), free cytosolic calcium (Cai2+) and free cytosolic sodium (Nai+) was studied in cultured vascular smooth muscle cells (VSMC) from rat aorta. Cells were loaded with either BCECF/AM, SBFI/AM or Fura-2 for measurement of pHi, Nai+ ... More
The effect of mechanical loading on the response of rat ventricular myocytes to acidosis.
AuthorsHongo K, White E, Orchard CH
JournalExp Physiol
PubMed ID8546860
'The effect of mechanical loading on the negative inotropic effect of acidosis in isolated rat ventricular myocytes was investigated. The mechanical loading of the myocytes was changed by attaching carbon fibres to the ends of the cell. To monitor intracellular Ca2+ and Na+ concentrations, cells were loaded with fluorescent dyes ... More
Spatial distribution of synaptically activated sodium concentration changes in cerebellar Purkinje neurons.
AuthorsCallaway JC, Ross WN
JournalJ Neurophysiol
PubMed ID9120555
'The spatial distribution of Na(+)-dependent events in guinea pig Purkinje cells was studied with a combination of high-speed imaging and simultaneous intracellular recording. Individual Purkinje cells in sagittal cerebellar slices were loaded with either fura-2 or the Na+ indicator sodium binding benzofuran isophthalate (SBFI) with sharp electrodes or patch electrodes ... More
Intracellular Na(+) concentration is elevated in heart failure but Na/K pump function is unchanged.
AuthorsDespa S, Islam MA, Weber CR, Pogwizd SM, Bers DM
JournalCirculation
PubMed ID12034663
'BACKGROUND: Intracellular sodium concentration ([Na(+)](i)) modulates cardiac contractile and electrical activity through Na/Ca exchange (NCX). Upregulation of NCX in heart failure (HF) may magnify the functional impact of altered [Na(+)](i). METHODS AND RESULTS: We measured [Na(+)](i) by using sodium binding benzofuran isophthalate in control and HF rabbit ventricular myocytes (HF ... More
Intracellular ramification of endothelin signal.
AuthorsIijima K, Lin L, Nasjletti A, Goligorsky MS
JournalAm J Physiol
PubMed ID2035621
'Effects of porcine 1-21 endothelin (ET-1) on [Ca2+]i, [Na+]i, and [Cl-]i and on membrane potential were studied in individual mesangial (MC) and vascular smooth muscle (VSMC) cells using microspectrofluorimetry of fura-2, SBFI, SPQ, and bis-oxonol, respectively. ET-1 increased [Ca2+]i by fivefold, showing an immediate and a sustained phase of response. ... More
The relationship between contraction and intracellular sodium in rat and guinea-pig ventricular myocytes.
AuthorsHarrison SM, McCall E, Boyett MR
JournalJ Physiol
PubMed ID1522523
'1. The contraction, measured optically, and the intracellular Na+ activity (aNai), measured with the Na(+)-sensitive fluorescent dye SBFI, have been recorded simultaneously in rat and guinea-pig ventricular myocytes. 2. In rat and guinea-pig ventricular myocytes at rest, aNai was 7.8 +/- 0.3 mM (n = 4) and 5.1 +/- 0.3 ... More
Neuronal nitric oxide synthase: its role and regulation in macula densa cells.
AuthorsKovács G, Komlósi P, Fuson A, Peti-Peterdi J, Rosivall L, Bell PD
JournalJ Am Soc Nephrol
PubMed ID14514725
'Macula densa (MD) cells detect changes in distal tubular sodium chloride concentration ([NaCl](L)), at least in part, through an apical Na:2Cl:K co-transporter. This co-transporter may be a site for regulation of tubuloglomerular feedback (TGF), and recently angiotensin II (Ang II) was shown to regulate the MD Na:2Cl:K co-transporter. In addition, ... More
Differential intracellular calcium responses to glutamate in type 1 and type 2 cultured brain astrocytes.
AuthorsJensen AM, Chiu SY
JournalJ Neurosci
PubMed ID1675265
'Fluorescence image analysis using the calcium indicator fluo-3 was used to examine changes in [Ca2+]i induced by glutamate in mixed glia populations cultured from neonatal rat brains. [Ca2+]i responses were correlated with glia type by performing immunohistochemistry using markers specific for type 1 and type 2 astrocytes on the same ... More
Measurement of intracellular Na+ concentration by a Na+-sensitive fluorescent dye, sodium-binding benzofuran isophthalate, in porcine adrenal chromaffin cells--usage of palytoxin as a Na+ ionophore.
AuthorsIto S, Ohta T, Kadota H, Kitamura N, Nakazato Y
JournalJ Neurosci Methods
PubMed ID9262139
'Palytoxin was found to equilibrate sodium ions (Na+) across the cell membrane much faster than dose gramicidin, which has been frequently used to calibrate the intracellular Na+ concentration ([Na+]in), in cells treated with a Na+-sensitive fluorescent dye, sodium-binding benzofuran isophthalate (SBFI). Palytoxin was capable of equilibrating Na+ in cells treated ... More
Increased tolerance to oxygen and glucose deprivation in astrocytes from Na(+)/H(+) exchanger isoform 1 null mice.
AuthorsKintner DB, Su G, Lenart B, Ballard AJ, Meyer JW, Ng LL, Shull GE, Sun D
JournalAm J Physiol Cell Physiol
PubMed ID15013953
'The ubiquitously expressed Na(+)/H(+) exchanger isoform 1 (NHE1) functions as a major intracellular pH (pH(i)) regulatory mechanism in many cell types, and in some tissues its activity may contribute to ischemic injury. In the present study, cortical astrocyte cultures from wild-type (NHE1(+/+)) and NHE1-deficient (NHE1(-/-)) mice were used to investigate ... More
The effect of mechanical deformation on the distribution of ions in fibroblasts.
AuthorsLeeves MA, McDonald F
JournalAm J Orthod Dentofacial Orthop
PubMed ID7771368
'The extracellular and intracellular sodium, potassium and chloride concentrations were determined in fibroblast cells located in the rat calvarium. The ionic values were determined by fluorescence microscopy after incubation with the fluorescent probes, sodium-binding benzofuran isophthalate (SBFI), potassium-binding benzofuran isophthalate (PBFI) and 6-methoxy-N-(3-sulfopropyl) quinolinium (SPQ) (Dyes were supplied by CALBIOCHEM, ... More
Na+,K(+)-ATPase activity in the cochlear lateral wall of the gerbil.
AuthorsFurukawa M, Ikeda K, Takeuchi S, Oshima T, Kikuchi T, Takasaka T
JournalNeurosci Lett
PubMed ID8873140
'We examined Na+,K(+)-ATPase activity in four regions of the gerbil cochlear lateral wall by measuring intracellular Na+ concentration ([Na+]i). The application of 1 mM ouabain and removal of external K+ caused a most striking increase in [Na+]i of the suprastrial fibrocytes, followed by the stria vascularis and the type II ... More
Na(+)-Ca2+ exchange in the isolated cochlear outer hair cells of the guinea-pig studied by fluorescence image microscopy.
AuthorsIkeda K, Saito Y, Nishiyama A, Takasaka T
JournalPflugers Arch
PubMed ID1614822
'The outer hair cell isolated from the guinea-pig was superfused in vitro and the cytosolic calcium concentration ([Ca2+]i) and sodium concentration ([Na+]i) were measured using fluorescence indicators. Under the resting condition, [Ca2+]i and [Na+]i were 91 +/- 9 nM (n = 51) and 110 +/- 5 mM (n = 12), ... More
Mutation of the protein kinase C phosphorylation site on rat alpha1 Na+,K+-ATPase alters regulation of intracellular Na+ and pH and influences cell shape and adhesiveness.
AuthorsBelusa R, Wang ZM, Matsubara T, Sahlgren B, Dulubova I, Nairn AC, Ruoslahti E, Greengard P, Aperia A
JournalJ Biol Chem
PubMed ID9242694
'The enzyme Na+,K+-ATPase creates the transmembrane Na+ gradient that is of vital importance for functioning of all eukaryotic cells. Na+, K+-ATPase can be phosphorylated by protein kinase A (PKA) and protein kinase C (PKC), and these sites of phosphorylation have been identified. In the present study, we have examined the ... More
Regulation of Na,K-adenosine triphosphatase gene expression by sodium ions in cultured neonatal rat cardiocytes.
AuthorsYamamoto K, Ikeda U, Seino Y, Tsuruya Y, Oguchi A, Okada K, Ishikawa S, Saito T, Kawakami K, Hara Y
JournalJ Clin Invest
PubMed ID8408640
'Na,K-ATPase (Na,K-pump) plays an important role in the regulation of intracellular ion composition. The purpose of this study is to determine whether Na+ regulates the levels of mRNA coding for Na,K-ATPase alpha and beta subunits in cultured neonatal rat cardiocytes. We measured intracellular Na+ levels ([Na+]i) in cardiocytes using a ... More
cAMP evokes a rise in intracellular Na+ mediated by Na+ pump inhibition in rat aortic smooth muscle cells.
AuthorsBorin ML
JournalAm J Physiol
PubMed ID7485457
'The effect of adenosine 3'',5''-cyclic monophosphate (cAMP) on intracellular Na+ concentration ([Na+]i) was studied in primary cultured vascular smooth muscle cells from rat aorta. [Na+]i was measured using digital imaging of cells loaded with the Na(+-)sensitive fluorescent dye sodium-bonding benzofuran isophthalate. The cAMP level was raised by 1) the membrane-permeable ... More
[Na+]i and the driving force of the Na+/Ca2+-exchanger in heart failure.
AuthorsBaartscheer A, Schumacher CA, Belterman CN, Coronel R, Fiolet JW
JournalCardiovasc Res
PubMed ID12650876
'OBJECTIVE: Diastolic calcium is increased in myocytes from failing hearts despite up-regulation of the principal calcium extruding mechanism the Na+/Ca2+-exchanger (NCX). We hypothesize that increased diastolic calcium ([Ca2+]i) is secondary to increased cytosolic sodium ([Na+]i) and decreased driving force of NCX (DeltaG(exch)). METHODS: The stimulation rate dependence of simultaneously measured ... More
Glucagon-like peptide-1 induces a cAMP-dependent increase of [Na+]i associated with insulin secretion in pancreatic beta-cells.
AuthorsMiura Y, Matsui H
JournalAm J Physiol Endocrinol Metab
PubMed ID14534075
'Glucagon-like peptide-1 (GLP-1) elevates the intracellular free calcium concentration ([Ca2+]i) and insulin secretion in a Na+-dependent manner. To investigate a possible role of Na ion in the action of GLP-1 on pancreatic islet cells, we measured the glucose-and GLP-1-induced intracellular Na+ concentration ([Na+]i), [Ca2+]i, and insulin secretion in hamster islet ... More
A novel monovalent cation channel activated by inositol trisphosphate in the plasma membrane of rat megakaryocytes.
AuthorsSomasundaram B, Mahaut-Smith MP
JournalJ Biol Chem
PubMed ID7542650
'The activation of a monovalent cation current was studied in rat megakaryocytes using patch clamp techniques combined with photometric measurements of intracellular concentrations of Ca2+ ([Ca2+]i) and Na+. ADP evoked a release of [Ca2+]i and transiently activated a monovalent cation-selective channel, which, at negative potentials and under physiological conditions, would ... More
Free and bound sodium in pancreatic beta-cells exposed to glucose and tolbutamide.
AuthorsAli L, Grapengiesser E, Gylfe E, Hellman B, Lund PE
JournalBiochem Biophys Res Commun
PubMed ID2679551
'The effects of glucose and tolbutamide on the sodium handling of the pancreatic beta-cells were evaluated by measuring the total sodium content in intact islets from ob/ob-mice by integrating flame photometry and the free ion in individual beta-cells by dual wavelength fluorometry. Whereas increasing the glucose concentration from 3 to ... More
Sodium-sensitive, calcium-independent potassium conductance in the leech giant glial cell
AuthorsNett W, Deitmer JW
JournalPflugers Arch
PubMed ID9683735
'We have measured membrane current, membrane potential and intracellular Na+ and Ca2+ concentrations, [Na+]i and [Ca2+]i, of the giant glial cell in the nervous system of the leech Hirudo medicinalis using conventional microelectrodes and the fluorescent dyes sodium-binding benzofuran isophthalate (SBFI) and fura-2. When the Na+ was removed from the ... More
Intracellular sodium in mammalian muscle fibers after eccentric contractions.
AuthorsYeung EW, Ballard HJ, Bourreau JP, Allen DG
JournalJ Appl Physiol
PubMed ID12588791
'The effect of eccentric contractions on intracellular Na(+) concentration ([Na(+)](i)) and its distribution were examined in isolated rat and mouse muscle fiber bundles. [Na(+)](i) was measured with either Na(+)-binding benzofuran isophthalate or sodium green. Ten isometric contractions had no significant effect on force (measured after 5 min of recovery) and ... More
Fluorometric analysis of intracellular sodium concentrations in isolated retinal horizontal cells.
AuthorsAndersen KA, Malchow RP
JournalBiol Bull
PubMed ID9818371
Angiotensin II and atrial natriuretic factor: cellular mechanisms in mammalian proximal tubule.
AuthorsHarris PJ
JournalExp Nephrol
PubMed ID8082001
Intracellular ion activities and membrane transport in parietal cells measured with fluorescent dyes.
AuthorsNegulescu PA, Machen TE
JournalMethods Enzymol
PubMed ID2074799
The purpose of this chapter is to summarize the methods we have usedfor measuring intracellular pH with BCECF, intracellular calcium with fura-2 and intracellular sodium with SBFI in single, identified cells of gastricglands isolated from rabbits. ... More
Intracellular free [Ca2+] and [Na+] in response to capsaicin in cultured dorsal root ganglion cells.
AuthorsAkerman KE, Grönblad M
JournalNeurosci Lett
PubMed ID1480318
Intracellular free Ca2+ and Na+ concentrations in cultured rat dorsal root ganglion cells were studied using the intracellular fluorescent probes fura-2 and SBFI, respectively. Capsaicin increased both intracellular [Ca2+] and [Na+]. A rise in cytosolic free Ca2+ could still be seen if Na+ was removed from the outer medium. The ... More
Cd2+ and Co2+ at micromolar concentrations stimulate catecholamine secretion by increasing the cytosolic free Ca2+ concentration in cat adrenal chromaffin cells.
AuthorsYamagami K, Nishimura S, Sorimachi M
JournalBrain Res
PubMed ID8069676
Cd2+ and Co2+ at micromolar concentrations increased the cytosolic free Ca2+ concentration, which was measured by fura-2 microfluorometry, in cat adrenal chromaffin cells. Simultaneously, these divalent cations stimulated catecholamine secretion from the perfused adrenal. The present findings suggest that these cations increase the Ca2+ influx by depolarizing the cell membrane ... More